Professor (博士, Hakase) is one of the main characters for the single player narrative. She can fight beside the protagonist during hunts in the single player main story. She placed fourth in Famitsu's character popularity survey.

Professor is an inventor in charge of creating new gizmos and gadgets; she created Tokitsugu's robotic body and the Demon Hand used by the protagonist. She frequently studies the ruins of ancient civilizations to search for "the world's truths".

Because people are uncertain of the Machina, which ranges from Tokitsugu's artificial body to her creation of the Demon Hand, she was called as the "Witch".